Engine/Transmission (1994 - 1998) Witnessed my first runaway toady..

[Boosted6]

Local fire department truck, wow that thing was blowing smoke to the point we thought it was on fire at one time... I don't know how they got it to shut down but after about 4 minutes it was over. . Fluids on the ground under it and firemen running all over the place. . they even turned the lights on while it was WOT. . I guess they did not know what else to do but walk away... .



Not a very good site to see this happen... Makes you wonder what if...

 

[bdcraig]

Imagine if that was your truck and you were alone. It will rattle you especially if you weren't expecting it. Kinda gets the addrialine flowing. Luckely I can see no outward damage to mine i. e. fluids all over the ground. Hopefully nothing internally was damaged.



Brian

 

[Boosted6]

Yes I read your post and I cannot imagine how you felt or feal, I know I would have probably paniced. . Bu the good thing is that you posted about yours and I know now to block the air intake incase this ever happens to me...



Thanks to everyone here!

 

[Vaughn MacKenzie]

In my 7-1/2 years on this board I've read about 5-6 runaways on a Dodge Cummins. All ended in catastrophic engine failure. One guy with a 3rd Gen said it buried the tach needle (which goes to 5000 RPM).



Since the engine is burning oil instead of diesel the governor has no impact in this situation. The only way to stop it is to cut off the air.

 

[Nate]

I'd rip the air cleaner off and hose it with a fire bottle.

 

[Msilbernagel]

I'd rip the air cleaner off and hose it with a fire bottle.

Just watch, some day someone will get their arm sucked into the intake...

 

[arthr31]

I read somewhere, maybe here, or on a tech website for a brand of diesel tractors, that with a runaway, you should not open the engine compartment hood since it allows a lot of free air flow. Instead, if you can, you should extinguish the fire with an extinguisher by point up in to the compartment from below. does this sound reasonable? Would it work? i guess at the moment of panic it might not seem sensible...

 

[PKemp]

Nate: don't do that. Leave the air cleaner connection and forget the fire bottle. That and they will not be useful. The most common cause of a runaway is the seal in the turbo. If the seal goes the turbo can suck oil directly out of the oil pan into the intake. This will "collect" in the intercooler turning it into a reservoir of "fuel". This you can't stop. The engine will burn its own oil as happily as diesel fuel. With no restriction on supply the engine will with great determination over-rev and self destruct. You don't have to inject fuel into the cylinders through the injector pump if the engine is running. The inertial rotation of the engine and the compression inside of the cylinders will become self sustaining and as long as it can get air - be unstoppable. Usually it will lock up because it has used up its own oil if it doesn't reach harmonic destruction first (around 4700 rpm). When the engine locks up the harmonic balancer on the crank will not be able to stop because of inertia and will spin the end of the crank off or spin off its rubber center. If your lucky it will stay in the engine compartment. If the rod bearings aren't stout enough one or more rods will exit the block.

The governor will not affect this scenario since the fuel supply isn't coming from the throttle. You must shut off the air. The best way to do that is to disconnect the air supply at the intake manifold feed horn. If you have nothing else disconnect the rubber air input connector at the feed horn (lacking other tools a razor knife around the intake horn works well), push it out of the way and stick a flat piece of plywood over the intake. The engine will die the quickest right here.



For our heavy diesel shop we have a local metal shop fabricate what we call a guillotine valve. It has a tube opening on one end connected to a flat box shaped piece connected to another tube shape. It goes between the intake rubber connector and the intake manifold (we add another short rubber "tube-to-tube" connector. There is a flat piece of heavy gauge galvanized steel with a handle on one end that sits like a square knife on the outside of the box inside a pair of "rails". You simply push it in (like a guillotine) to shut off the air. Works very effectively. Your local metal shop (the same people who build air/heating duct) can build you one. We put felt strips to act as seals/runners on the edges where the "knife" goes in to act as seals so there is no loss of boost pressure. We've tested them up to 45 psi with no loss of pressure. We also use these on our 18 wheelers. We are thinking about marketting them, but you can have one built for about $40 US. Its not pretty but you can have the outer surfaces powder coated in any color at more expense. I've seen 2 and the remains of 7 cummins B5. 9L engines that ranaway and self destructed. Since we started employing this "guillotine valve" idea and just a little training of the driver, it has been eliminated in our fleet of heavy diesels and service trucks.

 

[Woodenhead]

Nate: don't do that. Leave the air cleaner connection and forget the fire bottle. That and they will not be useful. The most common cause of a runaway is the seal in the turbo. If the seal goes the turbo can suck oil directly out of the oil pan into the intake. This will "collect" in the intercooler turning it into a reservoir of "fuel". This you can't stop. The engine will burn its own oil as happily as diesel fuel. With no restriction on supply the engine will with great determination over-rev and self destruct. You don't have to inject fuel into the cylinders through the injector pump if the engine is running. The inertial rotation of the engine and the compression inside of the cylinders will become self sustaining and as long as it can get air - be unstoppable. Usually it will lock up because it has used up its own oil if it doesn't reach harmonic destruction first (around 4700 rpm). When the engine locks up the harmonic balancer on the crank will not be able to stop because of inertia and will spin the end of the crank off or spin off its rubber center. If your lucky it will stay in the engine compartment. If the rod bearings aren't stout enough one or more rods will exit the block.

The governor will not affect this scenario since the fuel supply isn't coming from the throttle. You must shut off the air. The best way to do that is to disconnect the air supply at the intake manifold feed horn. If you have nothing else disconnect the rubber air input connector at the feed horn (lacking other tools a razor knife around the intake horn works well), push it out of the way and stick a flat piece of plywood over the intake. The engine will die the quickest right here.



For our heavy diesel shop we have a local metal shop fabricate what we call a guillotine valve. It has a tube opening on one end connected to a flat box shaped piece connected to another tube shape. It goes between the intake rubber connector and the intake manifold (we add another short rubber "tube-to-tube" connector. There is a flat piece of heavy gauge galvanized steel with a handle on one end that sits like a square knife on the outside of the box inside a pair of "rails". You simply push it in (like a guillotine) to shut off the air. Works very effectively. Your local metal shop (the same people who build air/heating duct) can build you one. We put felt strips to act as seals/runners on the edges where the "knife" goes in to act as seals so there is no loss of boost pressure. We've tested them up to 45 psi with no loss of pressure. We also use these on our 18 wheelers. We are thinking about marketting them, but you can have one built for about $40 US. Its not pretty but you can have the outer surfaces powder coated in any color at more expense. I've seen 2 and the remains of 7 cummins B5. 9L engines that ranaway and self destructed. Since we started employing this "guillotine valve" idea and just a little training of the driver, it has been eliminated in our fleet of heavy diesels and service trucks.

I did some work in Alberta and all the welding rigs we had on site had guillotine valves on them. No rig was allowed on a well site without having one installed. There's plenty of potential on site for flammable gasses to leak and if there's a running truck around it'll suck it up and it's goodbye time . I think these valves had some sort of method of closing automatically to kill the engine but I'm not sure.



Mike

 

[EKlem]

I read somewhere, maybe here, or on a tech website for a brand of diesel tractors, that with a runaway, you should not open the engine compartment hood since it allows a lot of free air flow. Instead, if you can, you should extinguish the fire with an extinguisher by point up in to the compartment from below. does this sound reasonable? Would it work? i guess at the moment of panic it might not seem sensible...

Most engine compartments will let a lot of air in so this will not make a difference. The place where it will make a difference is in marine engine compartments. The compartments have a pretty good seal and the air ductwork is sized to the engine. In a case like this, blocking the duct on the outside of the engine compartment can make a difference. I don't know the answer to whether a fire extinguisher from below would work.



If you are in your truck and are lucky to have a manual and be in a high gear already, you may be able to shut it down by standing on the brakes.



Anyone who has been around a runaway knows that they are real scary and very few people have the composure to try to do much about it. The only ways of succesfully stopping a runaway that I have seen were to shut off the air supply(a lot of the old detroits actually had a built in shut off), and to break the oil supply line off the turbo. Both of these take some real guts to be standing there and as mentioned above, there is definite potential to get seriously injured.

 

[Nate]

I don't understand how a fire extinguisher wouldn't work?



If your killing the oxygen... which is how a fire extinguiser works... . ain't gonna be a flame in the cylinders.

 

[MMiller]

On the old style V cat engines, when techs did fuel system work, before startup they would grab a heavy hammer. Then upon startup if their governor work was improper and it started running away, they would start knocking of injector lines. Also they said the safest place to be was on top of the engine.



At the last shop I worked at, there were many round, steel plates with handles on them and rubber glued to them, hanging on the wall. I was working on a governor, and before startup I leared always have something to block the air intake with. Well these plates hanging around the shop were just for this. Before startup you walked around to find the one that fit the inside of the filter box the best, then had somebody be ready when you fired it up. Its always best to have a thick book(service manual) clipboard, or something around to throw on the turbo during startup, especially after fuel system work, or turbo replacement.



Michael

 

[PKemp]

Nate: Its not so much that a fire ext wouldn't work, its about what kind and what volume (size) is enough to completely stop the air from getting through. You would have to pump foam in. Enough to completely choke off the intercooler. CO2, Dry powder, wouldn't do the job fast enough, water would create a hydro-lock in the cylinder and smash pistons (more damage). You have about 3-4 minutes before the engine has reached a point of no return. Cutting off the air supply at the intake manifold is the fastest, least contributing damage way to kill the engine. In a usual scenario you have probably just started the engine when the runaway begins. You are on the same side of the engine as the intake manifold horn, not the turbo side. Its quicker to disconnect the air tube from the intake horn than the turbo to cut off the air. You have also removed the "fuel" coming in from the leaking turbo seal thru the intercooler to the intake manifold. By blocking the turbo side you still have incoming fuel which will take longer to kill. Driver's side of the engine, quicker kill, less damage. Carry a nut driver in your glove box to fit the clamp on the intake horn connector. Time is of the essence. Also if you did manage to get enough foam in there to kill the engine and it survived with minimal damage, cleaning out the air intake system of what you just dumped in it is going to be very time consuming. After any runaway, the entire air intake system from the turbo to the intake manifold should be completely removed and thoroughly cleaned out. we use Calgon dishwashing detergent to clean out the intercooler. It works very well. If you don't clean it out your putting it back together with "fuel" in the intercooler that will just cause it to run away again.

 

[EKlem]

I don't understand how a fire extinguisher wouldn't work?



If your killing the oxygen... which is how a fire extinguiser works... . ain't gonna be a flame in the cylinders.

I was referring to sticking the end of the extinguisher in the general direction of the air intake and setting it off. With a big enough extinguisher of the correct type, you can definitely shut it down.



In boats(where most of my experience is), all of the the engine rooms have to have automatic fire extinguishing systems. They used to be halon but now they are fe241. These systems are primarily designed to deal with engine room fires but they are sized so that they will stop a runaway too.



The primary concern in a runaway is safety(unfortunately anything but a remotely operated air shutoff is dangerous) and then the next most important concern is to try to save the engine or at least its surroundings. The two ways to stop the runaway are to shut off the fuel and shut off the air because shutting off the heat is not practical(unless there is a compression release). If you are trying to shut off the fuel, knocking off injector lines or a turbo/blower oil line are the quickest ways. If you are trying to stop the air, it is pretty hard without a dedicated valve. Having seen a rubber foul weather gear jacket go through an engine, I have doubts about whether putting a piece of plywood over a rubber intake hose would stop it. I would think that the hose would suck in if you could get a good enough seal and then rupture. I haven't actually seen this but I am just guessing. The other way to shut off the air is to displace the oxygen. This is where the fire extinguisher comes in. The problem that I see with many fire extinguishers is that they are very corrosive so they would damage the engine unless you quickly tore it down.



In truth, most people with either stand back at a safe distance and watch the show or they will try whatever seems easiest and is often not very safe or good for the engine.

 

[jp8819]

Pretty scary thing when it happens and you have never seen one do it before. I saw one on a 4240 JD tractor when the govenor spring broke and it started overreving and kept getting worse. Stopped it by letting the 5 bottom plow down and getting into high gear fast and luckly the clutch held. Only other option was shoving something over the end of the air cleanier and its not the easiest to get to on one of those tractors plus you have to come out of the cab by the engine that is overreving.

 

[HallC]

I don't understand how a fire extinguisher wouldn't work?



If your killing the oxygen... which is how a fire extinguiser works... . ain't gonna be a flame in the cylinders.

Nate, here plain and simple reason it works. To stop any type of combustion rather it is open flame or the combustion in the engine you need to understand it what it takes to have combustion.



It takes 3 things to aquire combustion, Heat, Fuel and Oxygen. If you remove anyone of them, the combustion will not continue. On a diesel engine the fuel is diesel, the oxygen comes from the air intake and the heat is produced by the high compression in the cylinder.



When a diesel starts pulling engine oil past the turbo, shutting off the diesel fuel does no good. In fact, a diesel will run faster off engine oil that diesel fuel. The oil will fill the cooler so now shutting off its fuel source is nearly impossible.



Since the heat is generated by compression, unless you can find a way to stop the engine from turning, the compression will be there.



This brings us back to oxygen again. In my opinion, the best and easiest way to remove the oxygen is by using a CO2 extingisher in the air intake or air box. Halon or any inert gas will work as long as you can get enough to lower the oxygen below 14%.



Some say use a plywood board. If this is done, make sure it is a substanual piece of wood. I have a friend that had a military diesel run away on him while test it on a test stand. His first thought was kill the fuel but had no result. Then he took a clip board in his hand and put it against the open turbo intake and it accually broke the clip board and sucked it in. It finally ran out of oil and blow up sending pieces of rods and block all around.



Hope I never see one and if I do, I think I will stand to the front at a safe distance and watch the show.

 

[Thunderbolt]

I had 9 1/2 years on a 55' patrol boat with twin Detroit 8V92's. They ran away on me twice in all that time (thousands on metered running time). The Detroits had dampers installed in the intake which shut them down (snuffs 'em). The first time it happened I almost crapped myself. The mechanics said it was "hung injectors" They were mechanical rack injection engines I believe. The runaway sure gets your attention though.

 

[CToney]

Positive air shut down (Guillotine Valve) needed to work in the oil patch here in Canada. Roda Deaco valve is what is on our T800 Kenworth w/ N14. Never have tried it out though. No air no run.

 

[SnoKing]

Hey, I just ran to Bellingham to pick up some tile for the bathroom, came out to the tile store and hit the starter. Truck rev'd, died down, rev'd again and three times, and died as I shut it off. Start right back up without any issues. Installed new VP44 about a month and a half ago. Truck has been running super. Ideas? No codes! I normally get a slight flare in RPM's when starting, put nothing like this. SNOKING

 

[AFoulk]

I've never witnessed a runaway, but my teacher at tech school told me stories of them from his days at a Detroit dealer, back when the 2strokes were still Detroits thing. He said one time they had one runaway, and a guy stuck a service manual over the intake, but the idiot stuck it over the intake pages down and opened up. It just kept sucking pages it and spitting pieces of paper out the exhaust. I'd like to witness it someday, just from a distance